Adding cairo support to print/poppler

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

I would like to add cairo support to the poppler packages. The goal is to 
have a poppler-cairo-utils package that (indirectly, see below) depends on 
both poppler and cairo and provides pdftocairo (which is missing atm).

At present, print/poppler disables poppler's cairo support. If you enable it, 
you need cairo at build time (BUUILDLINK_DEPMETHOD.cairo=build; include 
cairo's bl3). However, the (stage-)installed files don't change, only a 
poppler-cairo.pc (currently provided by print/poppler-glib) is added. 
Some Makefile.am says "noinst_LTLIBRARIES = libpoppler-cairo.la".

So what's the best way to go (apart from adding a poppler-cairo-utils package)?

-- Add the build dependency to print/poppler, let it install poppler-cairo.pc 
   and remove it from print/poppler-glib's PLIST?

-- Add a poppler-cairo package (with a full dependency on cairo) that only 
   installs poppler-cairo.pc (removing it from print/poppler-glib)?

-- Leave it as is and let the new poppler-cairo-utils package depend on 
   poppler and cairo directly?

Any better name than poppler-cairo-utils? Just pdftocairo?